This disclosure relates to centrifuges for the separation of components of blood and similar fluids.
In an embodiment, this disclosure relates to a mechanism for securing a separation bowl to a mechanical chuck. Conventional blood processing devices exploit large centrifugal forces to separate the different components of whole blood by relying on the different densities of the different blood components, which can be separated and collected.
These blood processing devices may include a bowl, into which whole blood is inserted, a chuck, to which the bowl is secured, and a centrifuge motor, operably connected to the chuck. The centrifuge motor drives the chuck and the bowl secured thereto at very high speeds, thus allowing the separation of the different phases of blood.
A factor in the design of these devices is ensuring connection of the separation bowl to the chuck in order to avoid the undesired disengagement of the bowl from the chuck during operation with consequent damage to the bowl, the chuck and loss of blood product.
Different mechanisms for securing a separation bowl to a mechanical chuck have been developed over the years with the aim of allowing easy insertion and removal of the bowl from the chuck, while firmly securing the separation bowl to the chuck during operation.
For instance, U.S. Pat. No. 5,658,231 discloses a centrifugal chuck comprising a chuck housing provided with a plurality of slots, equally spaced along the circumference of the chuck, wherein gripping fingers are received. The gripping fingers are pivotally mounted around the outer perimeter of the chuck housing by means of pins and extend in a generally axial direction parallel to the axis of rotation of the centrifuge. Each gripping finger includes a tip portion, adapted to receive the base portion of a separation bowl thus securing the bowl to the chuck.
Another example of a mechanism for securing a separation bowl to a chuck is represented by a device developed by Sorin Group Italia S.r.l., and currently available under the trade designation ELECTA from Sorin Group Italia S.r.l. In such an arrangement, the bowl is permanently coupled with a cylindrical hollow body; this is adapted for coupling with a chuck (having an external diameter slightly smaller than the internal diameter of the hollow body) once the bowl is mounted thereon. The locking mechanism to secure the separation bowl to the chuck includes a spring-pin (i.e. a spring pushing radially a small ball or sphere) which cooperates with a slot provided in the internal surface of the hollow body firmly fixing the bowl bottom onto the chuck. The chuck includes a further safety locking system comprised of three locks urged radially outwardly by respective springs engaged in respective holes formed in the hollow body.
Despite the existence of mechanisms able to safely connect a separation bowl to a chuck, the inventors have noted that certain prior art clutching systems are not exempt from significant drawbacks. For instance, in the arrangement of U.S. Pat. No. 5,658,231, already cited, blood and dirt can easily enter the chuck and block it, with the ensuing risk that the bowl may detach from the chuck when turning at high speed.
The need is thus still felt for mechanisms which may allow simpler manufacturing and facilitate mounting the separation bowl on the chuck and removing the separation bowl from the chuck while ensuring improved protection of the internal volume of the chuck.